1-(2-furanylmethyl)-1h-pyrazolo(3,4-b)pyridine-5-methanones

ABSTRACT

New 1-(2-Furanylmethyl)-1H-pyrazolo(3,4-b)-pyridine-5-methanones are useful as anti-inflammatory agents.

United States Patent [191 Denzel et al.

[ 451 Dec. 24, 1974 1 Z-FURANYLMETHYL )-1H- PY RAZOLO( 3,4-B )PYRIDlNE-S- METHANONES Inventors: Theodor Denzel, Regensburg; Hans Hoehn, Tegernheim, both of Germany Assignee: E. R. Squibb & Sons Inc., Princeton,

Filed: Apr. 22, 1974 Appl. No.2 462,847

Related U.S. Application Data Continuation-impart of Ser. No. 361,120, May 17, 1973, which is a continuation-in-part of Ser. No. 292,363, Sept. 26, 1972, which is a continuation-inpart of Ser. No. 146,812, May 25, 19 7 1, abandoned.

US. Cl. 260/296 H, 260/240 J, 260/310 R,

424/263 Int. Cl C07d 49/20 Field of Search 260/296 H [56] References Cited UNITED STATES PATENTS 3,250,769 5/1966 Schmidt et al 260/247.1' 3,403,158 9/1968 Markillie..... 260/296 H 3,542,793 11/1970 Rossi et al.. 260/294 8 3,733,328 5/1973 Hoehn et a1. 260/293 6 3,736,327 5/1973 Denzel et al.... 260/296 H 3,787,430 l/I974 Hoehn et al. 260/296 H 3,810,905 5/1974 Hoehn et a1 260/295.5 B

FOREIGN PATENTS OR APPLICATIONS 2,225,433 12/1972 Germany 260/296 H Primary Examiner-John D. Randolph Attorney, Agent, or Firm-Lawrence S. Levinson; Merle J. Smith ABSTRACT New 1-(2-Furanylmethyl)-1H-pyrazol0[3 ,4-b]-pyridine-S-methanones are useful as anti-inflammatory agents.

14 Claims, N0 Drawings 1 1-(2-FURANYLMETHYL)-lH-PYRAZOL0(3,4- mr IuDI E-s- E rH oNEs This application is a continuation-in-part of application Ser. No. 361,120, filed May 17, 1973, which is a continuation-in-part of application Serial No. 292,363, filed Sept. 26, 1972, which is in turn a continuation-inpart of application Serial No. 146,812, filed May 25,

7 1971, arid haw abandoned.

SUMMARY OF THE INVENTION This invention relates to new l-(2-furanylmethyl)- 1H-pyrazolo[3,4-blpyridine-S-methanones which have the formula The symbols have the following meanings in formula 1 and throughout this specification. R is hydrogen or lower alkyl, R, is halo, hydroxy, lower alkoxy, amino or lower alkylamino. R is hydrogen, halo, lower alkyl or lower alkoxy. R is hydrogen, lower alkyl or phenyl.

DETAILED DESCRIPTION OF THE INVENTION and ethyl. All four halogens are included, but chlorine and bromine, especially the former, are preferred.

The products of the examples are representative of the various compounds of this invention and are preferred embodiments. Especially preferred compounds of formula I are those wherein R is hydrogen or methyl, R is hydroxy, lower alkoxy, especially ethoxy or amino, R is hydrogen, chloro, methyl or methoxy (preferably in the p-position), and R is hydrogen, methyl or phenyl especially hydrogen.

The new compounds of formula I are formed by the following series of reactions. The symbols in the structural formulas have the same meaning as previously described.

A S-aminopyrazole of the formula [produced by the procedure of British Pat. No. 1,057,740 or the procedure described in Z.f. Chemie 10, 386( 1970)], is made to react with an alkoxymethylene benzoylacetic acid esterof the formula [produced by the procedure described in Org. Synth. 28, 60-2( 1948)] by heating at a temperature of about l30C.

The resulting compound of the formula v Ra is cyclized in an inert organic solvent such as diphenyl ether at about 230 to about 260C. while distilling off the alcohol formed, producing a compound of the for mula This 4-hydroxy compound is refluxed for several hours with a phosphorus halide like phosphorus oxychloride to obtain a compound of the formula Hal represents halogen, preferably chlorine.

Treatment of the product of formula V1 with ammonia or a lower alkylamine at ambient or elevated temperature, e.g., up to about C., yields a product of formula I wherein R is amino or lower alkylamino, respectively.

Treatment of a compound of formula V with an al kylating agent, e.g., an alkyl halide like ethyl iodide, yields a compound of formula I wherein R is lower alkoxy, i.e.,

(VII) O-lower alkyl R;

Treatment of the compound of formula Vll with an amine as described above also yields a product of formula 1 wherein R is lower alkylamino.

According to a modification of the foregoing procedure a S-aminopyrazole of formula 11 is made to react with an acetoacetic acid ester derivative of the formula (VIII) R i k-CH; C 0 O-lower alkyl by heating in an organic solvent, e.g., at-reflux temperature, to obtain a compound of the formula R11 C O O-lower alkyl \N/-NH (l]:C\

H1 ll 1 o which is now cyclized as described above, producing compounds of formula V. This product is then treated with an agent such as sodium hydride and heated with a benzoyl halide of the formula yvhich produces a product of the formula l CH1 tion and constitute preferred embodiments. Other members of the class are produced by appropriate substitution of the starting materials using these as models. All temperatures are in degrees celsius.

EXAMPLE 1 4-Ethoxy-l-(2-Furanylmethyl)-1H-Pyrazolo[3,4- b]Pyridine-5-phenylmethanone a. 2-Benzoyl-3-{ l-(2-furanylmethyl)-5- pyrazolylamino] crotonic acid, ethyl ester 163 g. of 1-(2 furanyl)methyl-S-aminopyrazole (1 mol.) and 248 g. of ethoxymethylene benzoyl acetic acid ethyl ester (1 mol.) are heated at 130 until no more alcohol distils off (approximately 1 hour). The oily residue crystallizes and yields on cooling and recrystallization from hexane 319 g. of 2-benzoyl-3- [1-( Z-furanylmethyl )-5-pyrazolylaminolcrotonic acid, ethyl ester 7577. b. 4-Hydroxy-l-(2-furanylmethyl)-lH-pyrazolol3,4- b lpyridine-S-phenylme thanone 31.9 g. of 2-Benzoyl-3-[1-(2-furanylmethyl)-5- pyrazolylamino]crotonic acid ethyl ester are dissolved in'50 ml. of diphenyl ether and refluxed at 260 for 30 minutes. Distillation of the solvent yields a dark oil, which crystallizes on addition of methanol. Recrystallization yields 20 g. of 4-hydroxy-l-(2-furanylmethyl)- ll-l-pyrazolol 3,4-b]pyridine-5-phenylmethanone (61%), m.p. 102. c. 4-Ethoxyl 2-furanylmethyl l H-pyrazolol 3 ,4- blpyridine-S-phenylmethanone 3.3 g. of 4hydroxy-l-(2-furanylmethyl)-1H- pyrazolol3,4-blpyridine-S-phenylmethanone (0.01 mol.) are dissolved in 20 ml. of dimethylformamide. 2.8 g. of potassium carbonate and 3.1 g. of ethyl iodide are added and the mixture is warmed for 12 hours at 60. Excess potassium carbonate is filtered off and water is added. 4-Ethoxy-l-(2-furanylmethyl)-lH- pyrazolo[3,4-b]-pyridine-5-phenylmethanone precipitates and is recrystallized from hexane, yield 3 g. (86%), m.p. 70.

EXAMPLE 2 4-Amino-l-(2-Furanylmethyl)-3-Methyl-1H- Pyrazolol3,4-b]Pyridine-5-Phenylmethanone a. 2-Benzoyl-3-[ l-( Z-furanylmethyl )-3-methy1-5 pyrazolylaminol-crotonic acid, ethyl ester 177 g. of S-amino-l-(2-furanylmethyl)-3- methylpyrazole (1 mol.) and 248 g. of ethoxy methylene-benzoylacetic acid ethyl ester (1 mol.) are heated with stirring at and at the same time the alcohol formed is distilled off. The temperature is maintained for one hour. The reaction product, 2-benzoyl- 3-11-(2-furanylmethyl)-3-methyl-5- pyrazolylaminolcrotonic acid, ethyl ester, is crystallized with ether, yield 363 g. (96%), m.p. 82-83". b. 4-Hydroxy-l-(Z-furanylmethyl)-3'methyl-1H- pyrazolo[3,4-b]-pyridine-5-phenylmethanone 189.5 g. of benzoy1-3-[ l-(2-furanylmethyl)-3- methyl-S-pyrazolylaminolcrotonic acid, ethyl ester, (0.5 mol.) are dissolved in 500 ml. of diphenylether at 240 and this temperature is maintained for two additional hours with stirring. The alcohol formed is continuously distilled off during the reaction. After the solvent is removed in vacuo, the residual of 4-hydroxy-l- (2-furanylmethyl )-3-methyl-l H-pyrazolo[ 3 ,4- b]pyridine-5-phenylmethanone crystallizes on addition of 200 ml. of methanol, yield 121 g. (72%), mp. 130-131 (methanol).

c. 4-Ethoxy-1-(2-furanylmethy1)-3-methy1-1H- pyrazolo-[3,4-b1pyridine-5-phenylmethanone 33.3 g. of 4-hydroxy-1-(2-furanylmethyl)-3-methy1- lH-pyrazolo[ 3,4-b]pyridine-S-phenylmethanone (0.1 mol.), 16.5 g. of potassium carbonate and 17 g. of ethyl iodide are heated with stirring in 100 ml. of dimethylcontinuously by means of a water separator. After this time, the benzene is removed in vacuo and the residual 1-(2-furanylmethy1)-5-pyrazolylliminoacetoacetic acid, ethyl ester, is crystallized with ether, yield 220 g. (80%), mp. 4546 (methanol).

b. 2-( 3-chlorobenzoyl )-3-[ 1 2-furany1methyl )-3 methyl-5-pyrazoly1aminolcrotonic acid, ethyl ester 275 g. of [1-( 2-furany|methyl)-5- pyrazolyl]iminoacetoacetic acid, ethyl ester, (1 mol.) are carefully added to a suspension of 30 g. of sodium hydride in 1.5 liter of anhydrous dioxane with stirring. After the addition is completed, the mixture is refluxed for one hour and then 162 g. of m-chlorobenzoyl chloride are added dropwise. Refluxing is continued for ten hours. The mixture is now carefully acidefied with acetic acid and evaporated to dryness. The resulting oily residue is extracted three times with 300 ml. portions of ether. After evaporation of the solvent the residual 2-(3-chlorobenzoyl)-3-[l (2-furanylmethyl)-3- formfimlde for 10 hours at The inorganic l' methyl-5-pyrazolylamino]crotonic acid, ethyl ester, is tate 1S filtered offand the solvent removed. Recrystallicrystallized with ether, yield 280 (68%), zation of the resulting Oil yields 26 g. of 4-ethoxy-l -(2- o furanylmethyl)-3-methyl-1H-pyrazolo[ijA-bl pyridinec. 4 hydroxy l 2 furany1methy] 5-phenylmethanone (72%) 115 418 (metha' pyrazolo-[3,4-b]pyridine-5-(3-chloro)phenylmethanol). one d. 4-Amino-1-(2-furanylmethyl)-3-methyl-1H- 41.4 g. of(3-chlorobenzoyl)3-[1-(2-furanylmethyl)- pyrazolo[3,4-bl-pyridine-S-phenylmethanone 3-methyl-5-pyrazolylaminolcrotonic acid, ethyl ester 36.] g. of 4-ethoxy-l-(Z-furanylmethyl)-3-methylare heated for 10 minutes at 250255. After this time, 1H-pyrazolo[3,4-b]pyridine-S-phenylmethanone (0.1 the oily compound is cooled to room temperature as mol.) are dissolved in 100 ml. of butyl alcohol and quickly as possible. After the addition of 100 ml. of treated with ml. of aqueous concentrated'am monia methanol, the product, 4 hydroxy-l-(2- in an autoclave at 150 for 10 hours. After this time, the furanylmethyl)-6-methyl-lH-pyrazolol 3,4-b]pyridinesolvent is distilled off in vacuo and the residual 4- 5-(3-chloro)phenylmethanone crystallizes, yield 20 g. amino-1-(2-furanylmethy1)-3-methyl-1H-pyrazolo[3,4- (54%), mp. 23840 (butanol). b]pyridine-S-phenylmethanone if recrystallized from 35 The following intermediates are synthesized accordalcohol, yield 21.5 g. mp. 154-i56 (ethnaol). ing to procedure 2a or 312 as indicated:

Rs R 3 l| N LNHC=C/ \N 1 R4 COOR 01.12

Yield, Pro- Example R1 R3 R4 M.P. percent cedure 4 H p-Ci H 105-108 83 2a. 5 H p-OH; H 91-92 2a. 6 H -oom H 87-89 82 2a. 7 CH3 H 221 lOiiy, not further purified I 8 H H 9 H m-ci CH: 99-100 68 3b. 10 H CH3 Oily, not purified. 3b.

EXAMPLE 3 60 EXAMPLE 11 4-Hydroxy-l-(2-Furanylmethyl)-6-Methyl-1H- Pyrazolo[3,4-b]-Pyrid1ne-5-(3-Chloro)Phenylmetha- 4 chloro l (2 fumnylmethy1) 1H pyrazolol34 none a. [1-(Z-furanylmethyl)-5-pyrazolyl]iminoacetoacetic blpyndme 5 phenylmethanone acid, ethyl ester 65 31.9 g. of 4-hydroxy-1-(2-furanylmethyl)-1H- 163 g. of S-amino-1 (2-furanylmethyl)pyrazole and 130 g. of acetoacetic acid ethyl ester are refluxed for ten hours in benzene. The water formed is distilled off pyrazolo[ 3,4-b ]pyridine-5-phenylmethanone (0.1 mol.) are treated with 100 ml. of phosphorus oxychloride at for 10 hours. The excess phosphorus oxychloride is removed in vacuo and the residue poured into ice water. The mixture is extracted three times with 100 ml. portions of petroleum ether. The organic layer is dried over calcium chloride, evaporated and the residual pyrazo lo[3,4-b]pyridine--phenylmethanone is recrystallized from petroleum ether, yield 78-79".

The following additional products 5.4 g. (16%), m.p.

are synthesized by 4-chloro-l-(2-furanylmethyl)-lH- 5 the procedure of the Example indicated by substituting the appropriately substituted reactant:

wherein R is hydrogen or lower alkyl; R -is hydroxy,

lower alkoxy, halo, amino or lower alkylamino; R is hydrogen, halo, lower alkyl or lower alkoxy; and R is hydrogen, lower alkyl or phenyl.

2. A compound as in claim 1 wherein R, is hydrogen or methyl; R is hydroxy, lower alkoxy or amino; R is hydrogen, chloro, methyl or methoxy; and R is hydro- 3. A compound as in claim 1 wherein R R and R 4. A compound as in claim 1 wherein R is hydroxy.

I r gen, methyl or phenyl.

each IS hydrogen.

Yield, Proce- Example R R2 R R M.P. percent dure NH: 13-01 H 205-208 71 2d. 0H p-Cl H 125-126 58 30. 00535 p-Cl H 128-130 78 2c. 0 CzHs p-O CH3 H 122-124 75 20. OH p-OCHa H 125-127 64 30. OH III-CH3 H 129-131 62 3C. 0 321-15 p-CH: H 104-105 78 20.

O CaHs H 78-79 65 10.

OH H Q 215-216 48 3:).

Example R R R R M.P. yield procedure 2i H OH H CH 252-254 61'?! 3c 22 H OC H H CH 97-99 69% 2c 23 H oicHn cmcHo, H H 55-56 586 2c 24 H OC H m-Cl CH lOO-lOl 72% Zr 25 H NHC H H H 135-137 SW: 211 26 H NH H H l82l84 777! 2d CH NHCH(CH )-C H H 2d What is claimed is: 1. A compound of the formula 5. A compound as in claim 1 wherein R is lower alkoxy.

6. A compound as in claim 1 wherein R is amino.

7. A compound as in claim 1 wherein R is lower alkylamino.

8. A compound as in claim 1 wherein R R and R each is hydrogen and R is hydroxy. 9. A compound as in claim 1 wherein R is lower alkyl, R is amino and R and R is hydrogen.

10. A .compound as in claim 9 wherein the lower alkyl group is methyl.

11. A compound as in claim 1 wherein R is methyl, R is hydroxy, R is chloro and R is hydrogen.

12. A compound as in claim 1 wherein R is chloro, and R R and R each is hydrogen.

13. A compound as in claim I wherein R and R each is hydrogen, R is hydroxy and R is methyl.

14. A compound as in claim 1 wherein R and R each is hydrogen, R is hydroxy and R is phenyl. 

1. A COMPOUND OF THE FORMULA
 2. A compound as in claim 1 wherein R1 is hydrogen or methyl; R2 is hydroxy, lower alkoxy or amino; R3 is hydrogen, chloro, methyl or methoxy; and R4 is hydrogen, methyl or phenyl.
 3. A compound as in claim 1 wherein R1, R3 and R4 each is hydrogen.
 4. A compound as in claim 1 wherein R2 is hydroxy.
 5. A compound as in claim 1 wherein R2 is lower alkoxy.
 6. A compound as in claim 1 wherein R2 is amino.
 7. A compound as in claim 1 wherein R2 is lower alkylamino.
 8. A compound as in claim 1 wherein R1, R3 and R4 each is hydrogen and R2 is hydroxy.
 9. A compound as in claim 1 wherein R1 is lower alkyl, R2 is amino and R3 and R4 is hydrogen.
 10. A compound as in claim 9 wherein the lower alkyl group is methyl.
 11. A compound as in claim 1 wherein R1 is methyl, R2 is hydroxy, R3 is chloro and R4 is hydrogen.
 12. A compound as in claim 1 wherein R2 is chloro, and R1, R3 and R4 each is hydrogen.
 13. A compound as in claim 1 wherein R1 and R4 each is hydrogen, R2 is hydroxy and R3 is methyl.
 14. A compound as in claim 1 wherein R1 and R3 each is hydrogen, R2 is hydroxy and R4 is phenyl. 